1. Field of the Invention
This invention is directed to an apparatus for cooling or quenching product by direct quenching. More specifically, the apparatus has particular application to cooling the effluent from pyrolysis furnaces.
2. Description of the Prior Art
In the production of ethylene and similar products, it is customary to thermally crack hydrocarbons at high temperatures. The cracked effluent is then rapidly cooled or quenched by either direct, indirect or a combination of direct-indirect cooling means.
Rapid quenching of effluent is attended by the problem of fouling which results from the production of tars, coke, heavy polymers or other fouling material during the rapid cooling. These fouling products tend to coat the walls of the quench apparatus and inimically affect the heat transfer rate of the apparatus and, in some cases, clog the apparatus. As a result, shut down of the pyrolysis plant or the employment of on-stream cleaning techniques is necessary to rid the quench apparatus of the fouling materials. The practitioners in the art have attempted to develop various techniques for the avoidance of accumulation of fouling material on the quenching apparatus. One successful method developed is to flow a film of quench oil down the sides of the wall of a direct quencher continuously during periods of the quenching operation. U.S. Pat. No. 3,593,968 (Geddes; July 20, 1971) discloses a process and apparatus for continuously flowing quench oil down the sides of a direct quencher wall during operation to reduce the accumulation of tars, polymers and other fouling components thereon.